Problem with attenuation is homogenous media

Hello,
I am trying to evaluate attenuation in homogeneous media.
Using 3D simulation with a round transducer and a square sensor the pressure is computed at the same point in media without attenuation (a0) and in the same media by introducing attenuation (a1).
Using "medium.alpha_coeff =3 dB/cm" and "medium.alpha_power = 1.01", at a distance of 20mm from the emitter the difference between a0 an a1 should be 6dB (50% of decreasing).
The pressure values obtained in simulation (using peak to peak or maximum values) indicate only a decreasing of around 10% after introduction of attenuation.

The absorption in k-Wave follows a frequency power law, meaning that different frequencies are absorbed different amounts. The units of medium.alpha_coeff are actually dB/(MHz^y cm). In your example, the short tone-burst has a relatively broad frequency range. Thus, while the 1 MHz component will be absorbed by 3 dB/cm, the higher frequencies will be absorbed more, and the lower frequencies will be absorbed less. The wave will also change shape as it propagates due to dispersion linked with absorption (in this case physical, not numerical). This means just taking the maximum or peak-to-peak will not yield the desired absorption values.

Thank you for your tip concerning the variation of the attenuation due to the broadband of the excitation pulse. In fact I found an error in my code in the definition of the central frequency of the pulse that give rise to a wrong calculation of the attenuation. After correction everything is ok.